Temperature Indicator Module

[David VB]

Hi,

I would like to use the Temperature Indicator Module of a PIC10F322 to make a fan run at a PWM ratio depending of the temperature.

In my use case, the temperature can vary between 30 and 50 °C

The result must NOT be precise, since I will add a pot on one of the ADC pins to adjust the speed

I am using the formulas given in AN1333 ( https://www.microchip.com/en-us/application-notes/an1333 ) to get default values of the ADC for a given temperature.

But I get results which seem to be wrong, because the resolution sems completely off:

(Remember: the ADC in 10F322 is only 8-bits)

Temp ADC
30 139
31 140
32 140
33 140
34 140
35 141
36 141
37 141
38 142
39 142
40 142
41 142
42 143
43 143
44 143
45 143
46 144
47 144
48 144
49 145
50 145

Maybe I converted the formula not correctly ?   Here it is, for the second column of the first data line:

=((5-(4*(0,659-((A2+40)*0,00132))))/5)*255

Has anyone already worked with that Internal Temperature Indicator ?
Is my formula above correct ?

Any help is welcome !

Thanks,

David

[Rob CJ]

Hi David,

The formula says:  VDD - Mode * (0,659 etc.)

I assume Mode is 4 but you are using:   VDD - (Mode * (0,659 etc) which is not the same.

Kind regards,

Rob

---

Van: jal...@googlegroups.com <jal...@googlegroups.com> namens David VB <pinhe...@gmail.com>
Verzonden: woensdag 5 juni 2024 08:58
Aan: jallist <jal...@googlegroups.com>
Onderwerp: [jallist] Temperature Indicator Module

 

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[David VB]

Hi,

thanks Rob,

I changed the formula to =((5-4*(0,659-((A2+40)*0,00132)))/5)*1023

The new results are:

30 559
31 560
32 561
33 563
34 564
35 565
36 566
37 567
38 568
39 569
40 570
41 571
42 572
43 573
44 574
45 575
0   527
-40 484
100 635

Does this seem coherent to you ?

Thanks !